Instrument fault diagnosis method for high-risk complex scene
By combining the 1oo1D architecture with the IEC61508 standard, and employing a dual-CPU comparison mechanism and failure mode analysis, the fault diagnosis problem of temperature instruments in high-risk and complex scenarios has been solved, achieving high reliability and safety, and meeting the safety requirements of high-risk industries such as petrochemicals.
Patent Information
- Application Number
- CN202510756235.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-08
- Publication Date
- 2025-11-07
AI Technical Summary
Existing temperature instruments are prone to failure in different environments, affecting the reliability and safety of monitoring, and cannot guarantee stable operation, especially in high-risk and complex scenarios.
The system adopts a 1oo1D architecture, combines an MCU for data processing and comparison, adds a security layer to diagnose the sensors and communication components, selects diagnostic methods based on the IEC61508 standard, and introduces a dual-CPU comparison mechanism and failure mode analysis to ensure system safety and reliability.
It improves the fault diagnosis capability of temperature instruments in high-risk and complex scenarios, ensures system continuity and data processing accuracy, meets the requirements of high safety and availability, reduces the dangerous failure rate, and achieves the safety integrity level SIL2.
Smart Images
Figure CN120907693A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of instrument fault diagnosis, and particularly relates to a high-risk complex scene instrument fault diagnosis method. BACKGROUND
[0002] With the rapid growth of the economy and the continuous increase in infrastructure investment, the safety of the production environment and personnel safety have become the focus of social attention. In this context, the safety instrument system as a key technology to ensure the safety of industrial production, its importance is increasingly prominent. Safety instrument system can monitor the potential hazards that may occur in the production process in real time, and timely issue an alarm or automatically execute a safety program to prevent accidents and mitigate the harm and impact that may be caused.
[0003] Among the many safety instruments, temperature instruments play a crucial role. The above-mentioned technology has the problem that temperature instruments are not only responsible for temperature data collection and transmission, but also must have high reliability and safety to ensure stable operation under extreme or dangerous conditions. However, the temperature instruments in the prior art may fail in different environments, thereby affecting monitoring. SUMMARY
[0004] In view of the problems existing in the prior art, the application provides a high-risk complex scene instrument fault diagnosis method which can overcome the above problems or at least partially solve the above problems.
[0005] The application is implemented as follows: a high-risk complex scene instrument fault diagnosis method, S1, the temperature instrument adopts a 1oo1D architecture, and the data collected by the MCU and the data processing MCU are operated and finally compared. The sensor is diagnosed in the collection part, and the open circuit and short circuit of the sensor can be diagnosed. A safety layer is added in the communication part to ensure the safety of the communication data;
[0006] S2, at the same time, the data processing MCU periodically diagnoses the communication MCU to ensure the safe operation of the communication function of the communication MCU,
[0007] S3, the system structure and the corresponding diagnosis method are introduced in detail in the high-reliability safety standard IEC61508-2. IEC61508-2 lists the diagnosis methods and corresponding diagnosis coverage that must be considered for complex devices. Combined with the structure and characteristics of the high-reliability safety temperature instrument, the corresponding diagnosis function and diagnosis method are selected.
[0008] Preferably, for safety integrity evaluation, the relevant formula given by IEC61508-6 is as follows:
[0009] Hazardous failure rate: λ D = λDU + lambda DD = 1.118 x 10 -7 / h
[0010] Diagnostic coverage:
[0011] Safety failure fraction:
[0012] Total safety failure rate: lambda S + lambda DD = 4.431 x 10 -7
[0013] Total failure rate: lambda S + lambda DD + lambda DU = 4.534 x 10 -7 .
[0014] Preferably, the high-reliability safety temperature instrument is mainly composed of a collection part, a data processing part, a communication part and a power supply in structure.
[0015] Preferably, the collection part completes temperature data collection and calculation, and the calculation result is sent to the data processing part through a serial port, the data processing part calculates the transmitted data, and the communication part modulates and sends the data to a bus to make it a signal meeting the FF or PA protocol that can be recognized by a bus controller.
[0016] Preferably, in addition to the basic collection and transmission functions, the high-reliability safety temperature instrument adds diagnostic functions to parts that may fail, so that once failure occurs, the instrument can find the problem through a self-diagnosis circuit or program, and the instrument enters a safe state to ensure that the instrument is in a safe state and does not send any unreliable information to the bus.
[0017] Compared with the prior art, the present application has the following advantages:
[0018] The diagnostic circuit is designed, which can monitor and diagnose the input, output and processor of the temperature instrument in real time, thereby ensuring the continuity and reliability of the system. Secondly, the double-CPU comparison mechanism is introduced, through which the processing results of the temperature instrument at different operating stages can be compared and verified to improve the accuracy of data processing and the safety of the system. Finally, the failure mode, effects and diagnostic analysis (FEMEDA) method is used to calculate and analyze the dangerous failure rate (PFD) of the temperature instrument, so as to ensure that the design can meet the safety requirements of high-risk industries such as petrochemical industry. The comprehensive application of these methods aims to improve the performance of the temperature instrument and ensure its high safety and usability in critical applications. BRIEF DESCRIPTION OF DRAWINGS
[0019] Figure 1 is a high-reliability and safety temperature instrument structure schematic diagram provided by the embodiment of the present application;
[0020] Figure 2 is a temperature instrument structure schematic diagram provided by the embodiment of the present application with diagnosis;
[0021] Figure 3 is a high-reliability and safety temperature instrument diagnosis function and method schematic diagram provided by the embodiment of the present application;
[0022] Figure 4 is an FMEDA analysis result schematic diagram provided by the embodiment of the present application;
[0023] Figure 5 is a 1oo1D temperature instrument reliability block diagram provided by the embodiment of the present application;
[0024] Figure 6 is a failure probability of the function test provided by the embodiment of the present application. DETAILED DESCRIPTION
[0025] In order to further understand the invention content, characteristics and effects of the present application, the following embodiments are exemplified and described in detail as follows in conjunction with the drawings.
[0026] The structure of the present application will be described in detail below in conjunction with the drawings.
[0027] As shown in Figures 1 to 6 , the high-risk and complex scene instrument fault diagnosis method provided by the embodiment of the present application, S1, the temperature instrument adopts 1oo1D system structure, through the data operation and the final comparison of the collection MCU and the data processing MCU, the sensor is diagnosed in the collection part, the open circuit and the short circuit of the sensor can be diagnosed, the safety layer is added in the communication part, and the safety of the communication data is ensured;
[0028] S2, at the same time, the data processing MCU will periodically diagnose the communication MCU, to ensure the safe operation of the communication function of the communication MCU,
[0029] S3, the system structure and the corresponding diagnosis method are introduced in detail in the high-reliability and safety standard IEC61508-2, the diagnosis method and the corresponding diagnosis coverage must be considered for the complex device in IEC61508-2, the corresponding diagnosis function and diagnosis method are selected in combination with the structure and characteristics of the high-reliability and safety temperature instrument.
[0030] For safety integrity evaluation, the related formula given by IEC61508-6 is as follows:
[0031] Dangerous failure rate: λ D = λDU + λ DD = 1.118 x 10 -7 / h
[0032] Diagnostic coverage:
[0033] Safety failure fraction:
[0034] Total safety failure rate: λ S + λ DD = 4.431 x 10 -7
[0035] Total failure rate: λ S + λ DD + λ DU = 4.534 x 10 -7 .
[0036] The high-reliability safety temperature instrument is mainly composed of a collection part, a data processing part, a communication part and a power supply in structure.
[0037] The collection part collects and calculates temperature data, and the calculation result is sent to the data processing part through a serial port. The data processing part calculates the transmitted data, and the communication part modulates and sends the data to the bus to make it a signal meeting the FF or PA protocol that can be recognized by the bus controller.
[0038] In addition to the basic collection and transmission functions, the high-reliability safety temperature instrument adds diagnostic functions to the parts that may fail. Once failure occurs, the instrument will discover the problem through self-diagnostic circuits or programs, and the instrument will enter a safe state to ensure that the instrument is in a safe state and does not send any unreliable information to the bus.
[0039] The high-reliability safety temperature instrument adopts a redundant hardware architecture. According to the high-reliability safety standard IEC61508, the temperature instrument belongs to TYPEB system, and the design requirement is safety integrity SIL2, so the design goal is 99%>SFF>90%. For the redundant structure temperature instrument, in order to improve the diagnostic coverage, the temperature instrument adds corresponding diagnostic methods to diagnose the collection module, the data processing module and the communication module, and reduces the failure risk to make the safety integrity reach the SIL2 standard.
[0040] In the working process of the instrument, the instrument periodically diagnoses each part of the circuit through the diagnosis function, wherein the diagnosis function includes diagnosing the sensor module, the EEPROM module, the external RAM module and the power module, and when any part is diagnosed as having an error, the instrument enters a safe state; a double-CPU comparison method is used to compare the processing results of each stage of the instrument, so as to realize error correction diagnosis and processing result comparison, thereby ensuring safe and reliable operation of the system; when the calculated data of each stage of the acquisition MCU and the main MCU are consistent, the temperature instrument function is executed during the temperature measurement process without any fault, and when the calculated data of each stage of the acquisition MCU and the main MCU are inconsistent, the temperature instrument immediately enters a safe state to ensure the safety of the output signal, thereby reducing the risk failure rate and improving the diagnostic coverage:
[0041] Failure mode, effects and diagnostic analysis (FMEDA)
[0042] FMEDA is a method of detailed analysis of different failure modes and diagnostic capabilities of equipment, and the main factors considered by FMEDA technology mainly include the following points: the characteristics of all components included in the design product, the failure mode of each component, the influence of the failure mode of each component on the function of the product, the ability of automatic diagnostic detection of failure, environmental impact factors, etc.
[0043] For a high-reliability and safety temperature instrument, the safety integrity level is an important indicator for measuring the safety performance of the entire instrument, and IEC61508 proposes the concept of safety integrity level (SIL), that is, the probability of successfully implementing the required safety function of the safety instrument system within a specified time under specified conditions.
[0044] FMEDA analysis needs to complete the measurement of two safety integrity levels; namely: safety failure fraction SFF and average failure probability PFD of executing design function requirements. The failure mode and distribution data used in FMEDA analysis are derived from mechanical safety standard IEC62061, and the failure data are derived from Siemens internal reliability standard SN29500, and the diagnostic coverage corresponding to each failure mode is selected according to high-reliability and safety standard IEC61508. The analysis process of FMEDA is complicated and complex, and only part of the devices for FMEDA analysis and the final data of the analysis are listed in this paper.
[0045] In high-reliability and safety standard IEC61508, various parameters used in FMEDA analysis are described in detail, and only the parameters used are listed in this paper, wherein λS is the total safety failure rate, λDU is the total undetected dangerous failure rate, λDD is the total detected dangerous failure rate, and λNE is the probability of having no effect on the failure rate.
[0046] For the 1oo1D architecture, the dangerous failure rate of the channel can be considered to be composed of two parts, one part is the dangerous failure rate caused by undetected failure λDU, and the other part has the dangerous failure rate caused by detected failure λDD, wherein λDU affects the generated stop time tc1 is determined with the test test time interval T1 and the average recovery time MTTR, T1 is in the range of 1h-87600h (10 years), and λDD affects the generated stop time only related to the average recovery time MTTR.
[0047] The equivalent average stop working time tCE of the channel is equal to the sum of the respective stop working time tc1 and tc2 of the two parts, and the equivalent average stop working time tCE is proportional to the contribution of each part to the channel failure probability:
[0048]
[0049] According to the high reliability and safety standard IEC61508-6, for a channel with a shutdown time tCE caused by dangerous failure, the required time failure probability is:
[0050] PFD=1-e λ D t CE
[0051] Corresponding to different test test time T1 (1h-87600h), we can draw the curve of PFD with tCE by MATLAB software, wherein PFDavg is the average failure probability.
[0052] PFD increases with time, which is almost a linear change, and the average failure probability PFDavg is the average value of PFD, which is 0.0048.
[0053] Through the analysis of the calculation results, the safety failure fraction SFF=97.77%, the hardware fault margin of the 1oo1D architecture of the design is 0, and 99%>SFF>90%, so the safety failure fraction SFF of the instrument at this time reaches the safety integrity level SIL2; the average failure probability PFDavg=0.0048, and 10-3
[0054] It is to be noted that, in the present text, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.
[0055] The above descriptions are only the preferred embodiment of the application, not intended to limit the application in any aspect. Although the application has been disclosed with the preferred embodiments, it is not intended to limit the application, and any person skilled in the art can make modifications without departing from the scope of the application.
Claims
1. A method for instrument fault diagnosis of high-risk complex scenes, characterized in that: Comprise; S1, temperature instrument adopts 1oo1D architecture, through the acquisition MCU and data processing MCU carries out data operation and final comparison, diagnoses sensor in acquisition part, can diagnose the open circuit, short circuit of sensor, adds security layer in communication part, guarantees the safety of communication data; S2, at the same time, data processing MCU will carry out periodic diagnosis to communication MCU, ensure the safe operation of communication MCU communication function, S3, in the high reliability and safety standard IEC61508-2, the system structure and the corresponding diagnostic method are introduced in detail, IEC61508-2 lists the diagnostic method and the corresponding diagnostic coverage that must be considered for complex devices, combined with the structure and characteristics of high reliability and safety temperature instrument, the corresponding diagnostic function and diagnostic method are selected.
2. The instrument fault diagnosis method for a high-risk complex scene according to claim 1, characterized in that: For safety integrity evaluation, the relevant formula given by IEC61508-6 is as follows: Failure rate: λ D = λ DU + λ DD = 1.118 x 10 -7 / h Diagnostic coverage: Safety failure score: Total safety failure rate: λ S + λ DD = 4.431 x 10 -7 Total failure rate: λ S + λ DD + λ DU = 4.534 x 10 -7 .
3. The method of claim 1, wherein the high-risk complex scene is a scene in which a plurality of instruments are used in a plurality of processes, and the plurality of processes are performed in a plurality of steps. High reliability and safety temperature instrument is mainly composed of acquisition part, data processing part, communication part and power supply from structure.
4. The method of claim 1, wherein the high-risk complex scene is a scene in which a plurality of instruments are used in a plurality of processes, and the plurality of processes are performed in a plurality of steps. The acquisition part completes the acquisition and calculation of temperature data, and the calculation result is sent to the data processing part through the serial port. The data processing part calculates the transmitted data, and the communication part modulates and sends the data to the bus, so that it becomes a signal that can be recognized by the bus controller and meets the FF or PA protocol.
5. The method of claim 1, wherein the high-risk complex scene is a scene in which a plurality of instruments are used in a plurality of processes, and the plurality of processes are performed in a plurality of steps. In addition to the basic acquisition and transmission function, the high reliability and safety temperature instrument also has a diagnostic function in the part that may fail. Once failure occurs, the instrument will find the problem through self-diagnosis circuit or program, and the instrument will enter a safe state to ensure that the instrument is in a safe state and does not send any unreliable information to the bus.